Lots of past students have asked me this question: When do I use ‘a’ and when do I use ‘an’?
You use ‘a’ when the word following it starts with a consonant.
a cat
a book
a big house
a yellow pair of pants
You use ‘an’ when the word following it starts with a vowel.
an apple
an angry man
an egg
an orange
There are exceptions:
If the word starts with a silent letter, and the next is a vowel, then you use ‘an’.
an hour
an honest mistake
Also, when ‘u’ has the sound like ‘y’ or when ‘o’ sounds like ‘w’, then you use ‘a’.
a union
a used piece of paper
a one-legged dog
Lastly, ‘m’ can sometimes be tricky and you will need to use ‘an’.
an MBA program